A softer thermal gap filler pad makes close contact between thermal interface material and offers better thermal performance. In most cases, customer requires a softer thermal gap filler pad, making the hardness as low as possible, maybe shore00 10 or shore00 20. So we explain the effect of hardness to thermal gap pad below:

Usually, the lower hardness, the better thermal performance. This means the softer thermal gap filler pad is better than the stiffer one, but that’s not an absolute definition. For example, a customer needs the thermal gap filler pad in size of 200x200x2.0mm, and requires a lower hardness of shore00 20. This requirement can be met easily, but it will cause other problem too.

If the thermal pad is too soft, it’s not convenient for the worker to carry in production, so does to operator in application, distortion will easily take place when we carry it. We need to considerate the thermal performance and manipulability comprehensively. So fiberglass reinforced is necessary for distortion, puncture and tear resistance.

GLPOLY study shows that the most of thermal interface materials suppliers test the hardness of thermal pad based on the materials itself without fiberglass, it means the test is based on bulk materials.